Researchers from Stanford led by Maximillian Diehn reported a urine‑based minimal residual disease (MRD) approach that accounts for mutations in tumor‑adjacent urothelium—so‑called field effect—using a tumor‑informed uCAPP‑seq strategy and a RePhyNERX statistical pipeline, published in Cell. The method distinguishes true tumor‑derived urine tumor DNA (utDNA) from age‑related somatic mutations (clonal cystopoiesis), improving specificity in postoperative surveillance. Applied to serial samples from 61 intermediate‑ or high‑risk NMIBC patients receiving TURBT and BCG, the assay defined molecular response groups correlating with tumor mutational burden and immune activation. The field‑aware approach could refine MRD detection in bladder cancer and influence monitoring and adjuvant therapy decisions.